WHAT IS A PALLASITE?
Meteorites are rocks that have fallen to Earth from space. They are the remains of long-dead planets and asteroids; many or most are believed to originate in the asteroid belt between Mars and Jupiter. Pallasites are an extremely rare class, accounting for only about 1% of all known meteorites. Pallasites are packed with beautiful translucent crystals of olivine (the semi-precious gemstone peridot) suspended in a nickel-iron matrix, very much like the bits of fruit in a slice of fruitcake, and are thought to have formed at the core/mantle boundary of an ancient celestial body.
When sliced and polished, pallasites are among the most beautiful of meteorites. The color of the olivine crystals can vary from a deep amber to light green depending on the particular meteorite being viewed. In thin slices of pallasites, the crystals are translucent to light. Unfortunately, thin slicing is a poor method of preparing pallasites as the crystals have little metal to hold them in the matrix.
Pallasites are very scarce and believed to have formed on differentiated bodies in the transition area between the metal-rich core and the olivine-rich mantle where the olivine could cool slowly enough to form relatively large crystals. The Brenham pallasite is a representative and relatively available example of this class.